A. Field of the Invention
The present invention relates generally to wheel and brake assemblies and more particularly to an assembly in which the wheel disc surface is employed as and in place of a conventional brake rotor. Still more particularly, the present invention relates to a wheel disc brake assembly for use with motorcycles or other vehicles.
B. Description of the Prior Art
The prior art will be described by reference to motorcycles, but it should be understood at the outset that the present invention may be used with other types of vehicles, such as automobiles, aircraft, bicycles and the like.
In a typical motorcycle wheel assembly, a plurality of spokes interconnect the hub and a flanged rim. The tire is mounted on the rim and a separate disc brake rotor is mounted adjacent the hub. A brake caliper is provided for applying frictional braking forces against the rotor to stop the motorcycle.
Several problems are inherent in the design of such motorcycle wheel assemblies. First, construction of a spoked wheel assembly requires a great deal of care to insure that the wheel is maintained in a round configuration. Many prior art systems include movable spokes to compensate for changes in the weight loading on the wheel as it rotates. Such wheel assemblies are subjected to a great variety of complex stress forces during cornering. A further problem results from the fact that braking forces are applied to the brake rotor in the central portion of the wheel, which in turn must be transmitted through the spokes to the rim and tire before the motorcycle can be stopped. Moreover, by employing a small disc rotor near the hub, the braking surface is quite small and air cooling thereof is reduced.
Several of these problems have been recognized in the prior art and various attempts have been made to overcome them. One such prior art attempt is described in the Blasse et al. U.S. Pat. No. 3,709,561 issued Jan. 9, 1973 for "Brake and Wheel Assembly for Motorcycles and the Like." The wheel assembly described in this patent includes a hub and flanged rim with a plurality of rigid spokes coupling them together. The spokes have an I-shaped cross-section and are tapered slightly as they extend to the wheel periphery. The patent indicates that the rigid, but lighweight, construction of the spokes, maintains the desired roundness and supports the wheel during rotation, turning and braking. The brake system employed in the Blasse et al. device includes an annular brake ring bolted or otherwise suitably attached to the rim. The ring can be attached to the right or left side of the rim. Braking forces are applied from a brake caliper attached to the motorcycle frame. The patent states that the use of the rim mounted brake ring increases the cooling of the braking surface, provides a larger area of braking surface and results in the braking forces being applied directly to the rim rather than being applied to the hub and transmitted to the rim through the spokes.
While not related to the preparation of a wheel assembly for a motorcycle, one additional piece of prior art will be described here, i.e. the present inventor's U.S. Pat. No. 4,049,090 issued Sept. 20, 1977 for "Brake Discs." The patent relates to a brake disc rotor of conventional shape and utility having reduced weight and improved thermal dissipation. The disc brake rotor configuration described in the patent includes an aluminum core with stainless steel sheets bonded on each side to form an integral disc. The disc includes a central apperture for surrounding the hub and a plurality of circumferentially located holes about the apperture for attaching the rotor to a brake spider as is known to the motorcycle art.
The prior art has yet to disclose a braking system and wheel assembly which overcomes all the above-noted disadvantages of the prior art. A system which does so would represent a significant advance in this art.